"In the wiretapping, despite all the momentum for a more assertive Congress, you're seeing Congress backing down, because there are many Republicans and even Democrats who are afraid of being seen as preventing the president from protecting the nation," says Julian Zelizer, a congressional historian at Boston University.

"With the port deal, it's the president who is seen as impeding national security, rather than the Congress. That gives Congress an opportunity to challenge the president - and to do so in a way that makes it look as if they are the ones protecting the public," he adds.

Over strong objections from Democrats, the Senate Intelligence Committee voted along party lines this week to leave the controversial NSA wiretapping program intact, although subject to expanded oversight. A similar accommodation with the Bush administration is under way in the House.

The disclosure of a secret program of eavesdropping without a warrant by the National Security Agency last December looked as if it would have more traction. Early reports suggested that the NSA may have engaged in a broad program of eavesdropping on Americans.

The Senate Judiciary Committee has held two hearings on the NSA program, after Chairman Arlen Specter (R) of Pennsylvania said that he was not convinced that the program, which many legal experts say violates the 1978 Foreign Intelligence Surveillance Act, was justified. Senators grilled Attorney General Alberto Gonzales on specifics of the program and challenged the White House for not consulting with Congress before bypassing the FISA process.

On Tuesday, Republicans on the Senate Intelligence panel, proposed a compromise worked out with the White House. The agreement creates a new subcommittee that will receive "full briefings" on the program. Another proposal allows surveillance of suspected terrorists for up to 45 days without a warrant.

While Democrats protested the plan as an abdication of congressional oversight, it may defuse the issue, analysts say.

"With the spying, it's hard to overcome the ultimate purpose of the administration, which is to combat terrorism. With the ports, it's almost the opposite," says Carl Tobias, professor of law at the University of Richmond. "The ports deal is an easier issue to explain to the public, because it seems to find the administration in a contradiction," he adds.

Indeed, Republicans - facing midterm elections that will decide whether they keep their majority status - are in no mood to blink over a ports deal with Dubai that has outraged many of their constituents.

At the risk of the first veto of the Bush presidency, House Republicans rushed to attach language effectively banning the deal to a must-past war and hurricane relief spending bill, expected on the floor for a vote next week. The move has the broad support of leadership and the GOP caucus, says a spokesman for Speaker Dennis Hastert.

"Our public is very concerned about a foreign country, especially from the Middle East, having a major role in our ports," says Rep. Jerry Lewis (R) of California, chairman of the House Appropriations Committee, which marked up the $92.2 billion FY 2006 supplemental on Thursday. "It is my intention to lay the foundation to block the deal," he added, on the eve of the committee markup.

At the same time, the Senate Armed Services committee is taking up broader legislation that would force foreign owners of US port facilities to divest any holdings deemed critical to national security.

Since 9/11, Congress has taken a back seat to the White House in the conduct of the war on terror, with a few notable exceptions. Last year, Sen. John McCain (R) of Arizona led a move to force the White House to explicitly ban torture in the treatment of detainees.

However, a promised investigation of whether the intelligence on the existence of weapons of mass destruction in Iraq was politically manipulated has been bogged down in the Senate Select Committee on Intelligence for more than two years.

"It won't happen in my lifetime," says Sen. Richard Durbin (D) of Illinois, the No. 2 Senate Democratic leader, who says he is "disgusted" that Republicans have refused to accept their oversight responsibilities on intelligence.